Movable parts built onto the stern ends of watercrafts with a flow claim are known, such as trim tabs, which can be activated manually, electrically or hydraulically, whereby the mechanical spindle as well as the electrical and hydraulic cylinder lean against the stern of a watercraft as described in U.S. Pat. No. 3,695,204
Watercraft lifts for swimmers or tenders are known as a means of transporting persons or dinghies more comfortably and safely into or out of the water as described in DE patent 199 63 057 C1.